Re: [MacPerl] Can't get sendmail to put subject right...

[Ronald J Kimball <rjk@linguist.dartmouth.edu>]

On Wed, Jul 26, 2000 at 10:05:33AM -0500, David Steffen wrote:
> > > I indeed read all those dest[0]'s from a file, and such the \n character
> >> is in the end.
> >> Solved it by removing the extra \n in the end of the To-command. (I, for
> >> some reason, don't like that chomp command).
> >
> >If you ever have a $dest[0] without a newline at the end, I hope you won't
> >have to ask the list why your headers are ending up on the same line...
> >
> >You should chomp $dest[0] and print the newline explicitly.
> 
> I was more or less idlely following this thread, when it got me to 
> thinking.  This is a case where you very much want to know the exact 
> state of something ($dest[0] in this case) so you know how to proceed.
> 
> Chomp is good for dealing with 0 or 1 newlines, but what if there are 
> 43 newlines at the end of $dest[0]?
> 
> I came up with two solutions that seem fairly robust to me:
> 
> 1) Chomp until done:
> for($l = chomp $dest[0]; $l; $l = chomp $dest[0]) { }

Why a loop?

{ local $/ = ''; chomp $dest[0] }

or

$dest[0] =~ s/\n+$//;


> The only problem with this is what if there are (multiple) newlines 
> embedded within $dest[0]?  This may seem ridiculous, but consider the 
> case where $dest[0] ends with two newlines followed by a space? 
> Thus, my other solution is:
> 
> $dest[0] =~ s/\n/ /g;

tr/// is better for character to character translations.

$dest[0] =~ tr/\n/ /;

or even

$dest[0] =~ tr/\n/ /s;


> This assumes that completely eliminating a newline within a list of 
> multiple addresses might be bad, but that excess whitespace is not a 
> problem.  I believe this to be true, but am not that much of a 
> sendmail expert.
> 
> Comments?

If $dest[0] is read in with $/ set to "\n", there cannot be more than one
newline at the end of $dest[0], nor any embedded newlines.  So, I would
read in the value of $dest[0], and then immediately chomp() it, to make it
clear that the two operations are related.  Personally, I wouldn't worry
about the other newline problems unless I changed how $dest[0] was filled.


Ronald

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